##C#, <s>252</s> <s>247</s> <s>245</s> <s>232</s> 216 Bytes ## The size is pretty bad compared to the other solutions but nevertheless... using System;using System.Linq;class p{static void Main(){var c="";var i=Console.ReadLine();var r=new Random();for(int b=0;b++<i.Count();){int d=r.Next(10);Console.Write((char)(i[b]+d));c+=d;}Console.Write("\n"+c);}} This is my second ever answer to a codegolf and I'm quite a beginner considering C# so I'd appreciate to hear how to get it shorter :) Ungolfed: using System; using System.Linq; class p { static void Main() { var c = ""; var i = Console.ReadLine(); var r = new Random(); for (int b = 0; b++ < i.Count();) { int d = r.Next(10); Console.Write((char)(i[b] + d)); c += d; } Console.Write("\n" + c); } } - Saved 5 Bytes thanks to @FryAmTheEggman - Saved 2 Bytes thanks to @theLambGoat - Saved 7 Bytes by removing `static` from class p - Saved 24 Bytes thanks to @milk